6E1-88 DRIVEABILITY AND EMISSIONS
Detonation/Spark Knock Symptom
Step Action Value(s) Yes No
DEFINITION: A mild to severe ping, usually worse under acceleration. The engine makes sharp metallic knocks
that change with throttle opening.
1
Was the On-Board Diagnostic (OBD) System Check
performed? -
Go to Step 2
Go to OBD
System
Check
2
1. Perform a bulletin search.
2. If a bulletin that addresses the symptom is found,
correct the condition as instructed in the bulletin.
Was a bulletin found that addresses the symptom?
-
Verify Repair Go to Step 3
3
Was a visual/physical check performed?
-
Go to Step 4
Go to
Visual/Physic
al Check
4
1. If scan tool readings are normal (refer to Typical Scan
Values) and there are no engine mechanical faults, fill
the fuel tank with a known quality gasoline that has a
minimum octane rating Showing on the applicable
specification list.
2. Re-evaluate the vehicle performance.
Is detonation present?
-
Go to Step 5 Verify Repair
5
1. Check for obvious overheating problems:
• Low engine coolant.
• Restricted air flow to radiator, or restricted water flow
through radiator.
• Incorrect coolant solution. It should be a 50/50 mix of
approved antifreeze/water.
2. If a problem is found, repair as necessary.
Was a problem found?
-
Verify repair Go to Step 6
6
Check fuel pressure. Refer to Fuel System Pressure Test.
Was a problem found?
-
Verify repair Go to Step 7
7
Check items that can cause the engine to run lean.
Refer to Diagnostic Aids in Diagnostic Trouble Code 44 (If
applicable).
Was a problem found?
- Verify repair Go to Step 8
8
Check spark plugs for proper heat range. Refer to General
Information.
Were incorrect spark plugs installed?
-
Verify repair Go to Step 9
9
1. Remove excessive carbon buildup with a top engine
cleaner. Refer to instructions on the top engine cleaner
can.
2. Re-evaluate vehicle performance.
Is detonation still present?
-
Go to Step 10 Verify repair
10
Check for an engine mechanical problem. Perform a
cylinder compression check. Refer to Engine Mechanical.
Was a problem found?
-
Verify repair Go to Step 11
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